B) If it costs £4 to buy 5 pens, how much will it cost to buy 8?

10 because you need to find how much one pen would cost. So you decide 5 and 4. the result would be 1.25 then you multiple the result by 8. you get 10

a complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1. because no real number satisfies this equation, i is called an imaginary number. has no real solution, since the square of a real number cannot be negative.